Rotary Vacuum Dryers offer clean, simple and effective method of drying wet cake , powder and even slurry. Labour and energy costs are minimal compared to tray dryers and product losses during handling are also negligible. Additionally valuable organic solvents can be conveniently condensed and recovered. This equipment can be used in drying process of various Pharmaceuticals, Intermediate Compounds, Fine Chemicals, Chemicals, Agro Chemicals, Pesticides, Insecticides, Dyes and Food Products
The drying in a rotary vacuum dryer is a batch operation under vacuum. It is possible to dry heat sensitive materials at well below boiling points of water and solvents. Drying time depends on material being dried, amount of solvent or water to be removed, desired final moisture content, permissible jacket temperature etc. The dryer is available in sizes ranging from 100 litres to 20,000 litres gross volume. The volume of wet material loaded into the dryer is usually restricted to 50% of gross volume.
These rotary vacuum dryer give drying, mixing and breaking effects simultaneously. Wet cake or slurry is fed through charging door, while the agitator is rotating in clockwise direction, vacuum is applied in the dryer and heating media is circulated in the jacket. Evaporation of moisture takes place under vacuum and vapours passes through the dust catcher into the condenser, where it is condensed and collected in the receiver. Dried material is discharged through discharge valve. The lump breaker rods are provided to achieve good drying effect.
PRINCIPLE OF SPIN FLASH DRYING
The Spin Flash Drying is more often in the line of an agitated fluidized bed system. The drying agitator works as rotor to break the lumps and the hot air enters at reasonably high velocities to give dynamic action to dry and disintegrate the product. Wet material is dispersed into a stream of heated air (or gas) which conveys it through a drying duct. Using the heat from the airstream, the material dries as it is conveyed. Product is separated using cyclones, and/or bag filters. Typically, cyclones are followed by scrubbers or bag filters for final cleaning of the exhaust gases to meet current emission requirements. For even greater thermal efficiency and where winterization is required, recycling of exhaust gases can be used. This partial gas recycle (PGR) configuration can be implemented on all our airstream drying systems as well as retrofitted on customer’s existing drying operations.
Flash dryers have been used to dry products in many industries including agrifood, chemical, mineral. A broad range of feed materials including powders, cakes, granules, flakes, pastes, gels, and slurries can be processed. For slurries, pastes, or sticky materials, back mixing of the wet feed with a portion of dry product to produce a suitable conditioned material is required.